Signal generation

ABSTRACT

In order to automatically add measured amounts of a catalyst or other substance to a chemical reaction as needed, a signal representing a specific reaction condition is utilized to generate a pulse which has a width representative of the magnitude of said signal. An integrator then adds the pulses and after a predetermined total pulse time triggers an actuating mechanism which performs the operations necessary to add a substance to the chemical reaction.

United States Patent [191 Thornhill et al.

11 E Re. 28,572

[ Reissued Oct. 14, 1975 SIGNAL GENERATION [75] Inventors: William J.Thornhill, Lexington,

Ky.; Richard O. Welty, Bartlesville, Okla. I

[73] Assignee: Phillips Petroleum Company,

Bartlesville, Okla.

[22] Filed: May 10, 1974 [21] Appl. No.: 468,880

Related U.S. Patent Documents U.S. Applications: [62] Division of Ser.No. 502,096, Oct. 22, 1965, Pat. No.

[52] U.S. Cl. 307/106 [51] Int. Cl. H03k 3/00 [58] Field of Search307/106; 137/455, 505, l37/505.13; 340/240, 222; 328/59, 60, 62, 69

[56] References Cited UNITED STATES PATENTS 3,181,0[4 4/1965 Clark307/106 Primary Examiner-Herman T. Hohauser [57 ABSTRACT In order toautomatically add measured amounts of a catalyst or other substance to achemical reaction as needed, a signal representing a specific reactioncondition is utilized to generate a pulse which has a widthrepresentative of the magnitude of said signal. An integrator then addsthe pulses and after a predetermined total pulse time triggers anactuating mechanism which performs the operations necessary to add asubstance to the chemical reaction.

9 Claims, 11 Drawing Figures SIGNAL 6 INTEGRATOR ACTUATING q 4 MECHANISMReissued oct. 14, 1975 Sheet 1 014 Re. 28,572

SIGNAL INTEGRATOR ACTUATING MECHANISM INTEGRATOR FIG. 2

Reissued Oct. 14, 1975 Sheet 2 014 Re. 28,572

l4 PSIG IN PIPE 44 7 PSIG IN PIPE 5 |0- PRESSURE SWITCH 30 u ACTUATIONPRESSURE u 6 PSlG FIG. 3

O l 2 3 4 5 6 7 8 9 IO Reissued Oct. 14, 1975 Sheet 3-0f4 Re. 28,572

G W m m L 5 w i O H g 0 g I." A u b c Reissued Oct. 14, 1975 Sheet 4 of4Re.

SIGNAL GENERATION Matter enclosed in heavy brackets]: I appears in theoriginal patent but forms no part of this reissue specification; matterprinted in italics indicates the additions made by reissue.

This application is a division of application Ser. No. 502,096,filedOct. 22, 1965, which issued as U.S. Pat. No. 3,467,905 on Sept. 16,1969.

In U.S. Pat. No. 3,167,398, the disclosure of which is incorporatedherein by reference, there is disclosed metering apparatus comprising arotatable member having a chamber extending therethrough, and means toalternately accumulate and discharge through said chamber as the memberis rotated measured amounts of material thereby insuring accurate andcontrolled feed rate of that material, e.g., catalyst, to a receiver,e.g., a polymerization reactor. The operation of such metering devicesrequires the rotatable member to be rotated through a finite arc toalign the chamber therein with the inlet and exit apertures of thedevice, pause a finite length of time to allow substantially completedischarge of the material in the chamber through the exit aperture andcharging of a second chamber to be subsequently discharged, and thenrotated through another finite arc to move and hold the chamber fromcommunication with the exit aperture until another measured amount ofmaterial is desired to be discharged. Generally, the cycle rate of suchmetering devices is presently manually set by an operator and rewhereinthe cycle rate of the metering device is responsive to at least oneprocess variable and/or at least one property of the product.

I However, it was found that conventional cyclic actuators could noteffect a sufficiently lengthy pause between the two arcs of rotation inthe cycle of the metering device and therefore did not allow sufficienttime for the chamber of the metering device to completely discharge thedesired quantity of material. Attempts to adjust these conventionalactuators only resulted in jerky, erratic motion causing considerableleakage of the metering device as well as increased wear and generallypoor performance of that device.

Broadly, a method of this invention involves producing a signal ofvariable time intervalconstant duration pulses which signal is inproportion to a signal representative of a measured process variableand/or a property of the product. This method includes first producing asignal of variable durationconstant time interval pulses which signal isproportional to the signal representative of the process and/or propertyand then converting that signal to the desired signal of variable timeintervalconstant duration pulses.

By variable durationconstant time interval pulses, it is meant a signal,be it electrical, hydraulic, pneumatic, and the like, which is broken upinto substantially constant time intervals and during each time intervalthere is produced a pulse, e.g., a flow of electrons, etc., which willlast .for a variable time duration depending upon the magnitude of thesignal representative of the process variable and/or property measured,but the maximum of which duration is equal to or less than the timeinterval in which that pulse is produced. For example, if the timeinterval is 10 seconds, a pulse produced during that time inverval canvary from 0 to 10 or slightly less than 10 seconds and if the signalrepresentative of the process variable and/or property increases inmagnitude, e.g., in the case of pneumatic signal increases in pressure,the time duration of each pulse in each time interval will increasetoward'the l0-second maximum until the first signal remains constant ordecreases in magnitude in which case the time duration of each pulse ineach time interval will become constant of each pulse in each timeinterval will become constant or decrease in length, respectively. Byvariable time intervalconstant duration pulses, it is meant a signalwherein each pulse produced lasts for the same time duration but thateach substantially constant time duration pulse is separated from theother by a variable time interval so that as the time duration of eachpulse in the variable time durationconstant time interval signalincreases in response to increase magnitude of the signal representativeof the process variable and/or property, the time interval between theconstant duration pulses in the variable time intervalconstant durationpulse signal becomes less and therefore is in proportion to themagnitude of the first signal representative of the process variableand/or property. Generally, the first signal as with the other signalsmentioned above can be electrical, pneumatic, hydraulic and the like,and is composed of a pulse having an indefinite and variable timeduration and having a varying magnitude during that time duration.

Further according to this invention a variable duration pulse generatoris provided which during substantially equal successive time intervalsproduces a source of fluid under pressure and passes said fluid past apressure switch and out of the system. Depending upon the pressure ofthe fluid passing through the pressure switch, that switch may not closeat all or may be closed for any length of time up to the length of thetime interval during which the fluid is passed through the pressureswitch. The variable duration pulse, ile., the time in each intervalduring which the pressure switch is closed, is accomplished by varyingthe rate of flow of the pressurized fluid through the pressure switch inresponse to the magnitude of the signal responsive to the measuredprocess variable and/or property of the product. This apparatus canfunction electrically, pneumatically, hydraulically, etc.

In the drawing,

FIG. 1 shows schematically a system utilizing the pulse generatingapparatus of this invention.

FIG. 2 shows a variable duration pulse generator of this invention.

FIG. 3 shows graphically operational characteristics of the apparatus ofFIG. 2.

FIG. 4 shows integrator apparatus suitable for use in the system of FIG.1.

FIG. 5 shows a metering device actuating mechanism.

FIG. 5A shows an alternative time delay means which can be used in themetering device actuating mechanism of FIG. 5.

FIG. 5B is a schematic electrical representation of solenoid actuatedrelay switch 98 which is shown in FIGS. 5 and 5A.

FIG. 6 shows relative relationships of the cams of the apparatus of FIG.during one cycle of operation.

FIG. 7 shows a metering device actuating mechanism.

FIG. 7A shows an alternative time delay means which can be used with themetering device actuating mechanism of FIG. 7.

FIG. 8 shows the relationships of the cam of the apparatus of FIG. 7through one cycle of operation.

FIG. 1 shows a variable duration pulse generator 1 connected to anintegrator 2 which in turn is connected to metering device actuatingmechanism 3. Actuating mechanism 3 is connected through shaft 4 tometering device 5. Signal 6 is the first signal or signal representativeof a measured process variable and/or property of the product. Ifdesired, first signal 6 can be an arbitrarily selected, manuallyproduced signal. As an example, signal 6 can be the output signal of aconventional temperature recorder controller which is operativelyconnected in a conventional manner through a differential thermocoupledevice to the interior of a pipe carrying therethrough cooling water onits way to the cooling jacket of a polymerization reactor. If signal 6is pneumatic, it is preferably in the range of 3 to psi. g. The senseddifferential temperature of the cooling water entering and leaving thejacket will determine the magnitude of the output signal of thetemperature recorder controller and it is this signal and the magnitudethereof which determines the duration of the pulse in each time intervalof the intermediate signal 7 put out by variable duration pulsegenerator 1. If the output signal of the temperature recorder controlleris, for example, pneumatic an increase in the pressure of this signal,representing an increase of temperature of the monomer in the pipe, isimpressed on the variable duration pulse generator and the effectsthereof are shown in detail in the discussion of FIG. 2, infra. Signal 7from generator 1 is then passed to integrator 2 which converts signal 7to signal 8 which signal is composed of a series of pulses each ofsubstantially the same time duration and each separated from the otherby variable time intervals. Signal 8 is then used to activate actuatingmechanism 3 which converts signal 8 to a rotary mechanical motionmanifested in the rotation of shaft 4 which in turn operates meteringdevice 5 in the cyclical manner required by that device. Metering device5 can be that apparatus disclosed in U.S. Pat. No. 3 ,167,398, andsimilar known types of apparatus.

Thus, due to the measured change of a process variable which is passedto generator 1 in the form of signal 6 the variable duration pulse putout by generator 1 in the form of signal 7 is changed accordingly andthe variable time interval put out by integrator 2 is also changedaccordingly so that the actuating mechanism 3 which operates in responseto signal 8 is also accordingly effected and in turn operates meteringdevice 5 in relation to the effect thereon by signal 8 thereby caus-'ing the cyclical operation of metering device 5 to be responsive to thechange in the process variable manifested in signal 6. If thetemperature of the monomer increases above normal the pressure of thepneumatic signal 6 increases which increases the duration of each pulsein each time interval of signal 7 which shortens the time intervalbetween constant duration pulses of signal 8 which actuates mechanism 3faster than is normal with the result that metering device 5 is operatedfaster than normal.

In FIG. 2 there is shown a variable duration pulse generator wherein acam switch 10 is driven by a motor 11 so that for a given interval oftime the cam switch is open a part of the interval and closed anotherpart of that interval, and this sequence is repeated continually therebyproducing a continuous series of substantially constant time intervals.Switch 10 and motor 11 are electrically connected by electrical lines 12and 13 so that motor 11 constantly drives cam switch 10 and when camswitch 10 is contacting element 14 an electrical circuit is closedbetween normally open solenoid valve 15 and normally closed solenoidvalve 16 by means of electrical lines 17, 18, and 19. Between valves 15and 16 is air accumulator 20 which is in open communication with valves15 and 16 through pipes 21 and 22, respectively. Accumulator 20 isopenly connected to a source of air through conduit 22, valve 16 andconduit 23. The amount of air passed into accumulator and therefore themaximum pressure of the air in accumulator 20 produced while normallyclosed valve 16 is open is controlled by needle valve 24.

Normally open pressure switch 30 is electrically connected to integrator2 through electrical lines 31, 32, and 33. Integrator 2 is alsoconnected to conduit 19 by electrical line 34. Pressure switch 30 isopenly connected through pipes 35, 36, and 37 to valve 15 andaccumulator 20. Throttle valve 38 is openly connected between pipes 36and 37 and adapted to vary the rate of flow of air from accumulator 20into pipe 36.

Pipe 36 is also in open communication with motor valve 39 through pipe40 and bleed valve 41 through pipe 42. Air from accumulator 20 passesout of the system via pipe 43. The rate at which air passes out of thesystem through 43 can be varied by varying the opening of throttle valve39 in response to the magnitude of the pressure of a pneumatic airsignal passing to motor valve 39 through pipe 44. The air signal inconduit 44 is the signal that is representative of the measured processvariable and/or property of the product.

In operation and by way of example, cam switch 10 and timing motor 11are adjusted to produce a time interval of 10 seconds. That is, thesubstantially constant time intervals in the signal passed to integrator2 through line 33 is 10 seconds. During the first portion of the 10second interval, about 2 seconds, the cam switch is actuated bycontacting member 14 thereby closing normally open valve 15 and openingnormally closed valve 16 so that air is passed into accumulator 20 andis allowed to accumulate to a predetermined maximum pressure, in thisexample 25 p.s.i.g. After passage of this first portion of the timeinterval cam switch 10 is deactivated by moving from contact with member14 and normally open valve 15 is opened and normally closed valve 16 isclosed thereby allowing the pressurized air in accumulator 20 to passthrough pipes 21, 37, 36, 40, and 43 out of the system and also intopipe 35 where sufiicient pressure will activate pressure switch 30.Bleed valve 41 is adjusted so that when motor valve 39 is substantiallycompletely closed, the pressurized air in accumulator 20 will be loweredto the actuation pressure of pressure switch 30 before the next 10second interval starts and accumulator 20 is repressurized with new air.Throttle valve 38 can be adjusted so that when motor valve 39 is wideopen the pressure in pipe 35 does not reach a pressure sufficient toactuate pressure switch 30, in this example 6 p.s.i.g. or is justsufiiciently high to actuate pressure switch 30 for only a small amountof time, for example about 3 seconds.

Thus, when signal 44 varies in magnitude, for example increases inpressure, the opening in motor valve 39 is pinched down to therebyrestrict the flow of air therethrough from pipe 40 thereby increasingthe pressure in pipe 35 and forcing pressure switch 30 closed for alonger period of time than is normal. When this is effected, a variableduration pulse, in this case of increased duration, is passed throughline 33 to integrator 2 during each second time interval. Therefore, avariable durationconstant time interval signal is passed to integrator2, the variable duration pulse of that signal being responsive to thesignal in pipe 44 which in turn is responsive to the measured processvariable or property of the product. Generally, the pneumatic signal inpipe 44 will vary from a 3 to p.s.i.g. magntiude.

If pressure switch 30 is adjusted so that under normal conditions it isclosed for a finite period of time, the pulse generator of thisinvention can send pulses of longer duration to the integrator inresponse to increased pressure of the signal in pipe 44 thereby speedingthe operation of integrator 2 or can keep pressure switch 30 open longerthan normal thereby sending pulses of shorter duration than normal tointegrator 2 thereby slowing the operation of that integrator inresponse to lower pressures than normal in pipe 44.

FIG. 3 shows a graph wherein time is plotted against pressure onpressure switch 30 so that when accumulator is charged up to a p.s.i.g.maximum and then allowed to pass its pressurized air out of the systemunder normal conditions, arbitrarily set as normal at a 7 p.s.i.g.signal in pipe 44, pressure switch will remain closed for 4 seconds.However, if the signal in pipe 44 increases to a magnitude of 14p.s.i.g. in response, for example, to a temperature increase of themonomer above-mentioned, motor valve 39 will be pinched down so that thepressurized air is not removed from the system until the end of theIO-second time interval and therefore pressure switch 30 stays closedfor substantially the whole time interval of 10 seconds.

Similarly, if the signal in pipe 44 should fall below the normal 7p.s.i.g. to 5 p.s.i.g., motor valve 39 will open further therebyallowing the pressurized air in accumulator 20 pass out of the systemmore rapidly and pressure switch 30 is thereby closed for only 3seconds. Thus, it can be seen that depending upon the magnitude of thesignal in pipe 44 the relation of the pulse sent to integrator 2 duringeach equal time interval will vary in direct proportion and pulsegenerator 1 is therefore supplying to integrator 2 a variableduration-constant time interval signal.

Although any type of conventional apparatus which can receive and storesignals of variable duration until a predetermined amount of thesesignals has been received and then produce a signal of constant durationpulses can be employed as an integrator of this invention, an example ofsuch apparatus is shown in FIG. 4. In integrator 2 of FIG. 4, there is atimer motor .50 which rotates a shaft 51 which in turn carries androtates two cam means 52 and 53 each with a similar indentation 54 and55 in the periphery thereof. Cam followers 56 and 57 are connected toelectrical switches 58 and 59.

The signal is transmitted from the variable duration pulse generator 1of FIG. 2 to timer motor 50 by electrical lines 60 and 61. Switch 58 isconnected to an electrical power source (not shown) by electrical line63 and to line 60 by electrical line 64. Electrical line 65 connects theelectrical supply source to line 61. Switch 59 is connected throughelectrical line 70, electrical power supply 71 and electrical line 72,and electrical line 73 to the metering device, actuating mechanism 3(not shown).

.In operation, during each 10 second time interval pulses of varyingduration pass by lines 60 and 61 to motor 50 thereby operating same andturning cams 52 and 53 for a time substantially the same as the durationof each pulse. When a sufficient number of pulses of sufficient durationhave operated motor 50 long enough to cause indentations 54 and 55 tocome into register with cam followers 56 and 57 switches 58 and 59 aretripped and a pulse is sent by way of lines 72 and 73 to actuatingmechanism 3. When switch 58 is tripped the electrical sources areconnected into motor 50 thereby causing same to continue to operateuntil cam follower 56 is disengaged from indentation 54 of cam 52 atwhich time switch 59 is also deactuated and the pulse to the actuatingmechanism terminated. Thus, a variable duration pulseconstant timeinterval signal from pulse generator 1 passes into integrator 2 by lines60 and 61 and a variable time intervalconstant duration pulse signal ispassed from integrator 2 by lines 72 and 73 to the actuating mechanism3.

FIG. 5 shows interval-actuating mechanism of this invention wherein thevariable time intervalconstant duration pulse signal from integrator 2is passed from electrical lines 72 and 73 to latching relay which isadapted by means of coil 81 to, upon receipt of a pulse from integrator2, switch contacting arm 82 from the contact on which it was left upontermination of the last received pulse (as shown in FIG. 5 contact 83)to the other contact 84 and latching relay 80. Contacts 83 and 84 areconnected by electrical conduits 85 and 86 to contacts 87 and 88 ofswitch 89. Switch 89 is connected by electrical line 90 to switch 91.Contact 92 is connected by way of electrical line 94 to switch which hastwo contacting arms 121 and 122 and three contacts 123, 124, and 125.Contacts 123 and 125 are connected through lines 126 and 127respectively to line 97 for control of solenoid actuated relay switch98. Details of the operation of solenoid actuated relay switch 98 areshown in FIG. 5B. Contact 124 is connected to the timing motor 128 byelectrical line 129. Timing motor 128 is also connected to conduit 73 byelectrical line 130. Shaft 131 of motor 128 carries cam 132 which coactswith cam follower 133 which is adapted to move contact arms 121 and 122between two of the contact points. Switch 98 is connected by electricalline 103 to electrical drive motor 104. Electrical line 186 of motor 104and 188 of switch 98 are connected to an electrical power source. Motor104 rotates shaft 105 which shaft carries cams 106 and 107 and whichshaft is connected to the rotatable member of metering device 5. Thus,when drive motor 104 rotates shaft 105 cams 106 and 107 and therotatable member of metering device 5 are all moved together. Camfollowers 108 and 109 engage, respectively, cams 106 and 107 and areadapted to trip switches 91 and 89 back and forth from their twocontacts.

In operation, the pulse passing through contacts 84, 88 and 92 passesthrough line 94, a contacting arm 121, contact 123 and lines 126 and 97to actuate switch 98 and start operation of motor 104. After motor 104has turned cam 106 90 it moves the contacting arm of switch 91 fromcontact 92 to 93 which causes the pulse to pass through conduit 99,contact arm 122, contact 124 and line 129 to start operation of timingmotor 128. Timing motor 128 turns cam 132 until cam 132 trips switch 120by moving contacting arms 121 and 122 into contact with contacts 124 and125, respectively. The time required to cause rotation of cam 132 sothat it will trip switch 120 is that amount of time required to allowthe chamber in the rotatable member of metering device to substantiallycompletely empty its contents. When switch 120 is tripped the pulseoriginally passing through contacting arm 122, contact 124 and line 129is then directed to contact 125 and lines 127 and 97 to reactivateswitch 98 and start motor 104 in operation again. After motor 104 hasturned cams 106 and 107 through another 90 arc contacting arm in switch91 is moved from contact 93 to 92 and the contacting arm in switch 89 ismoved from contact 88 to contact 87 and operation of the mechanismterminated. When the next pulse arrives it will be directed throughcontacts 83, 87, 92 and 124 thereby causing operation of timing motor128 until cam 132 reaches the point where it trips switch 120 back andthe pulse is then severed from contact 124 to contact 123 and therebyallows actuation of switch 98 and starts operation of motor 104, tostart a new cycle.

FIG. A shows an alternative delay means which can be used to replaceswitch 120, motor 128, cam 132, and cam follower 133 of the FIG. 5apparatus. Contact 92 of the apparatus shown in FIG. 5 is connected byway of electrical lines 95 and 97a to solenoid actuated relay switch 98.Contact 93 is connected by electrical line 100 to circuit delay device101, and lines 102 and 97a connect circuit delay device 101 to solenoidactuated relay switch 98.

In the operation of the device of FIG. 5 using this alternative circuitdelay device, a pulse received from integrator 2 causes contacting arm82 to switch from contact 83 to 84 and pass the pulse through contacts88 and 92 through lines 95 and 97a to switch 98 thereby causing it toclose and start motor 104 in operation. After motor 104 has rotated(together with cams 106 and 107 and rotatable member in metering device5) about 90, the contacting arm of switch 91 is transferred from contact92 to contact 93 thereby causing the pulse to pass into circuit delaydevice 101 which causes the pulse to be held up and thereby interruptsthe supply of electricity to switch 98 which causes that switch toreturn to its normally open position. The circuit delay device 101 canbe any conventionally known delay device such as a Cramer Type TEC-ISSStyle A time delay relay made by the R. W. Cramer Company, Inc.,Centerbrook, Connecticut. After a short interval of time which issufficient in length to allow the chamber in the rotatable member ofmetering device 5 to substantially completely empty the contentsthereof, the pulse is passed by lines 102 and 97a to switch 98 whichactuates and again starts motor 104 into operation. After motor 104 hasrotated cams 106 and 107 another 90, the contacting arm in switch 91 ismoved from contact 93 back to contact 92 and at the same time contactarm in switch 89 is passed from contact 88 to contact 87. When thecontacting arm in switch 89 is passed from contact 88 to contact 87, themechanism is deactivated and will not be reactivated until a new pulseis received from integrator 2 which pulse will then cause contact arm 82of switch to move from contact 84 to contact 83.

FIG. 5B is a schematic diagram of solenoid actuated relay switch 98 asit is connected in the apparatus of FIGS. 5 and 5A. When a signal isapplied to the coil of solenoid 98a through leads 190 and 97 (or 97a),

contact 98b is closed thereby making a connection between line 188 andline 103. When there is no signal applied to the solenoid 98a, contact98b returns to its open position.

FIG. 6 shows the relationship of cams 106 and 107 as they have rotatedthrough the three stages of each cycle of operation of this mechanism.In Stage A double lob cam 106 and single lob cam 107 are in a positionso that no switching will occur until rotated and 180, respectively.When motor 104 is operated for the first time cams 106 and 107 arerotated 90 at which time cam 106 trips switch 91 but cam 107 still has90 of rotation to follow through before it will trip switch 89. In StageC cam 106 is in position to trip switch 91 back to the position it wasin in Stage A while cam 107 has reached the first point where it is in aposition to trip switch 89 the first time. Thus, in a rotational arc of180, which is generally required by the metering device 5, cam 106 tripsswitch 91 twice while cam 107 trips switch 89 once to end'the cycle.

In FIG. 7 the pulse from integrator 2 passes to switch which has twocontacts 141 and 142. Switch 140 is connected through lines 143 and 144to switch 170 which has two contacting arms 171 and 172 connected tolines 143 and 144 respectively and three contacts 173, 174, and 175.Contacts 173 and 175 are connected by electrical lines 176 and 177 toelectrical line 178. Line 178 is connected to solenoid a which alongwith operating rod 15012 and valve 150e, is a part of normally closedsolenoid valve 150. Contact 174 is connected through electrical line 179to timer motor 180. Line 73 is connected to timer motor 180 through line181 and to solenoid 150a through line 182. Shaft 183 attached to motor180 carries cam 184. Cam follower 185 coacts with cam 184 to trip switch170 back and forth between the three contacts. Air passes from a source(not shown) to pipe 151, valve 150e, pipe 152 into pneumatic actuator153. Actuator 153 contains a threaded shaft 154 with a piston coactingwith the threaded portion and biased toward air inlet aperture 156 byresilient means 157. Air is vented from actuator 153 through vent 158.Shaft 154 is connected to shaft 159 by ratchet means 160. Shaft 159carries cam 161 and is attached to the rotatable member of meteringdevice 5. Cam follower 162 coacts with cam 161 and is adapted to tripswitch 140 back and forth from contacts 141 and 142.

In operation the pulse passing through contact 141 passes through line143, contact 173, and lines 176, 178, to operate solenoid 150a and openvalve 1500 and cause rotation of cam 161 through a 90 arc. After the 90rotation cam follower 162 trips switch 140 to contact 142 therebydeenergizing solenoid 150a, closing valve 150c and stopping rotation ofshaft 159 and passing the pulse through line 144, contact 174 and line179 to start operation of timer motor 180. After timer motor 180 rotatescam 184 cam follower 185 trips switch thereby moving contacting arm 172from contact 174 to contact and causing the pulse to pass through lines177, 178, and 149 to reopen valve 9 150c and cause cam 161 to be rotatedanother 90 at which time switch 140 is retripped and the contact armmoved back to contact 141. Here also the time required to cause cam 184to rotate a sufficient amount to trip switch 170 is that amount of timerequired to allow the chamber in the rotatable member of metering deviceto substantially completely empty its contents. After switch 140 isretripped back to contact 141 any pulse that is left is employed throughline 143, contacting arm 171, contact 174, and line 179 to continueoperation of timer motor 180. The first portion of the next pulse fromintegrator 2 is employed in like manner until cam 184 is rotated to aposition where it retrips switch 170 so that contacting arms 171 and 172are again in contact with contact 173 and 174, respectively.

FIG. 7A shows an alternative time delay device which can be used withthe apparatus of FIG. 7 in place of switch 170, motor 180, cam 184, andcam follower 185. Contact 142 of switch 140 is connected through line146 to circuit delay device 147 and then through lines 148 and 149 tosolenoid 150a of normally closed solenoid valve 150. Contact 141 isconnected to solenoid 150a through electrical lines 145 and 149. Circuitdelay device 147 can be the same type of device as disclosed in FIG. 5A.1

In operation of the apparatus of FIG. 7 utilizing the alternate delaymeans of FIG. 7A, the pulse from integrator 2 initially passes throughcontact 141 and lines 145 and 149 to solenoid 150a which opens valve150C and causes air to be admitted to actuator 153 for a time sufficientto push piston 155 the distance required to rotate shaft 154 and 159 andratchet 160 and cam 161 90 at which time cam follower 162 trips switch140 and transfers contacting arm to contact 142, thus deenergizingsolenoid 150a, closing valve 150c, and stopping rotation of shaft 159.The pulse then passes through line 146 into circuit delay device 147 andafter the time delay sufficient to allow contents of the chamber of therotatable member of metering device 5 to be substantially completelyremoved therefrom, the pulse is passed by lines 148 and 149 to reopenvalve 150c and admit air to actuator 153 thereby causing piston 155 toadvance another distance sufficient to cause rotation of cam 161sufficiently to cause cam follower 162 to retrip switch 140 and move thecontacting arm back to contact 141 and to complete the 180 rotation ofshaft 159 after which the duration of the pulse terminates and resilientmeans 157 forces the piston back toward the inlet end 156 of actuator153 which is accomplished without disturbing the rotatable member inmetering device 5 due to ratchet 160.

FIG. 8 shows double lob cam 161 and the three stages of rotation of eachcycle of operation. In Stage A valve 150 is opened for the first timeand cam 161 is then rotated 90 to the position of Stage B at which stagecam follower 162 trips switch 140 from contact 141 to contact 142. Whenvalve 150 reopens for the second time cam 161 is rotated another 90 tothat shown in Stage C at which point switch 140 is retripped fromcontact 142 back to contact 141.

EXAMPLE A 9 p.s.i.g. signal is fed into a Honeywell pulse transmitter(i.e., a variable duration pulse generator) Series 702 E 62 N having amaximum pulse rate of 540 p ses per hour, from which generator isobtained an electrical signal which is composed of a series of separate,

electric pulses about 5 seconds in duration, the period of durationvarying proportionally as the pneumatic signal fed into the generatorvaries in pressure magnitude. This variable duration signal is fed intoan Industrial Timer Corporation recycling cam switch and a Cramer TypeTEC-lSS Style A time delay relay, the two components making up theintegrator. An output electric signal is obtained from the integratorwhich is composed of a series of electrical pulses each pulse of whichis 4 seconds. The start of each pulse is separated from the start ofeach preceding pulse by a time period of 13.3 seconds which time periodvaries proportionally with the increase or decrease of duration of theelectrical pulses fed into the integrator. The output signal from theintegrator is fed into a Westinghouse solenoid piloted air operatedfour-way valve Cat. No. PD4- 41-9398 which controls the air flow to aBettis Corporation Model 301 180 pneumatic rotary actuating mechanismwith a 180 ratchet coupling which in turn is mechanically coupled to aball check metering device like that of US. Pat. No. 3 ,]67,398. Theactuating mechanism in response to the signal from the integratorrotates the captive ball valve of the metering device through a cycle ofrotation of the valve in a given direction-pauses 2 seconds-then rotatesthe valve a second 90 in the same direction-then stops.

Reasonable variations and modifications are possible within the scope ofthis disclosure without departing from the spirit and scope thereof.

What is claimed is:

1. A method for producing a resultant signal composed of a series ofpulses each having substantially equal time duration and each pulsebeing spaced from the other by a variable time interval, which resultantsignal is in proportion as to its variable time interval to a firstsignal of a varying magnitude, comprising producing in response to saidfirst signal an intermediate signal composed of a series of pulses eachhaving a variable time duration in proportion to the magnitude of saidfirst signal and each formed during one of a series of sequential timeintervals, each time interval being of substantially equal length, andthen producing in response to said intermediate signal said resultingsignal.

2. The method according to claim 1 wherein said pulses of saidintermediate signal are normally of a substantially equal time durationwhich is less than the length of one of said time intervals.

3. The method of claim 1 wherein said first signal is an electricalsignal and wherein said intermediate and resultant signals arerespective series of electrical. pulses.

4. Apparatus for producing a resultant signal composed of a series ofpulses each having a substantially equal time duration and each pulsebeing spaced from the other by a variable time interval, which resultantsignal is in proportion as to its variable time interval to a firstsignal having a varying magnitude, comprising a variable duration pulsegenerator means for forming in response to said first signal anintermediate signal composed of a series of pulses each having avariable time duration in proportion to the magnitude of said firstsignal and each formed during one of a series of sequential timeintervals, each said sequential time interval being of substantiallyequal length, and an integrator means connected to said pulse generatormeans for producing in response and in proportion to said intermediatesignal said resultant signal.

5. The apparatus of claim 4 wherein said pulse generating meanscomprises means to establish a plurality of electrical pulses ofconstant duration and at a constant frequency, a gas accumulator, inletconduit means to supply gas to said accumulator, outlet conduit means toremove gas from said accumulator, adjustable flow control means in saidoutlet conduit means to adjust the rate of removal of fluid from saidaccumulator, said adjustable flow control means being adapted to beadjusted by said first signal, means responsive to said plurality ofelectrical pulses to control flows through said inlet and outlet conduitmeans so as to pressure said accumulator at said constant frequency andto open said accumulator to said outlet conduit means at said constantfrequency, and means to pass signals to said integrator means responsiveto the pressure in said outlet conduit means.

6. The apparatus of claim 5 wherein said means to pass signals to saidintegrator comprises a source of electrical energy, circuit meansconnected to said source, a switch in said circuit means, and pressureresponsive means connected to said outlet conduit'means to close saidswitch whenever the pressure in said outlet conduit means exceeds apredetermined value.

7. The apparatus of claim 4 wherein said integrator means comprises amotor connected to said pulse generating means, at least one camconnected to said motor to be rotated thereby, a power source, circuitmeans connected to said power source to provide said resultant signal, aswitch in said circuit means, and

means responsive to said at least one cam to close said switch when saidmotor has rotated a predetermined amount and to rotate said motor anadditional amount to open said switch.

8. Signal generating apparatus comprising means to establish a pluralityof electrical pulses of constant duration and at a constant frequency, agas accumulator, inlet conduit means to supply gas to said accumulator,outlet conduit means to remove gas from said accumulator, adjustableflow control means in said outlet conduit means to adjust the rate ofremoval of fluid from said accumulator, said adjustable flow controlmeans being adapted to be adjusted by an input signal, means responsiveto said plurality of electrical pulses to control flows through saidinlet and outlet conduit means so as to pressure said accumulator atsaid constant frequency and to open said accumulator to said outletconduit means at said constant frequency, and means to establish anoutput signal whenever the pressure in said outlet conduit means exceedsa predetermined value.

9. The apparatus of claim 8 wherein said means to es tablish an outputsignal comprises a source of electrical energy, circuit means connectedto said source, a switch in said circuit means, and pressure responsivemeans connected to said outlet conduit means to close said switchwhenever the pressure in said outlet conduit means exceeds apredetermined value.

1. A method for producing a resultant signal composed of a series ofpulses each having substantially equal time duration and each pulsebeing spaced from the other by a variable time interval, which resultantsignal is in proportion as to its variable time interval to a firstsignal of a varying magnitude, comprising producing in response to saidfirst signal an intermediate signal composed of a series of pulses eachhaving a variable time duration in proportion to the magnitude of saidfirst signal and each formed during one of a series of sequential timeintervals, each time interval being of substantially equal length, andthen producing in response to said intermediate signal said resultingsignal.
 2. The method according to claim 1 wherein said pulses of saidintermediate signal are normally of a substantially equal time durationwhich is less than the length of one of said time intervals.
 3. Themethod of claim 1 wherein said first signal is an electrical signal andwherein said intermediate and resultant signals are respective series ofelectrical pulses.
 4. Apparatus for producing a resultant signalcomposed of a series of pulses each having a substantially equal timeduration and each pulse being spaced from the other by a variable timeinterval, which resultant signal is in proportion as to its variabletime interval to a first signal having a varying magnitude, comprising avariable duration pulse generator means for forming in response to saidfirst signal an intermediate signal composed of a series of pulses eachhaving a variable time duration in proportion to the magnitude of saidfirst signal and each formed during one of a series of sequential timeintervals, each said sequential time interval being of substantiallyequal length, and an integrator means connected to said pulse generatormeans for producing in response and in proportion to said intermediatesignal said resultant siGnal.
 5. The apparatus of claim 4 wherein saidpulse generating means comprises means to establish a plurality ofelectrical pulses of constant duration and at a constant frequency, agas accumulator, inlet conduit means to supply gas to said accumulator,outlet conduit means to remove gas from said accumulator, adjustableflow control means in said outlet conduit means to adjust the rate ofremoval of fluid from said accumulator, said adjustable flow controlmeans being adapted to be adjusted by said first signal, meansresponsive to said plurality of electrical pulses to control flowsthrough said inlet and outlet conduit means so as to pressure saidaccumulator at said constant frequency and to open said accumulator tosaid outlet conduit means at said constant frequency, and means to passsignals to said integrator means responsive to the pressure in saidoutlet conduit means.
 6. The apparatus of claim 5 wherein said means topass signals to said integrator comprises a source of electrical energy,circuit means connected to said source, a switch in said circuit means,and pressure responsive means connected to said outlet conduit means toclose said switch whenever the pressure in said outlet conduit meansexceeds a predetermined value.
 7. The apparatus of claim 4 wherein saidintegrator means comprises a motor connected to said pulse generatingmeans, at least one cam connected to said motor to be rotated thereby, apower source, circuit means connected to said power source to providesaid resultant signal, a switch in said circuit means, and meansresponsive to said at least one cam to close said switch when said motorhas rotated a predetermined amount and to rotate said motor anadditional amount to open said switch.
 8. Signal generating apparatuscomprising means to establish a plurality of electrical pulses ofconstant duration and at a constant frequency, a gas accumulator, inletconduit means to supply gas to said accumulator, outlet conduit means toremove gas from said accumulator, adjustable flow control means in saidoutlet conduit means to adjust the rate of removal of fluid from saidaccumulator, said adjustable flow control means being adapted to beadjusted by an input signal, means responsive to said plurality ofelectrical pulses to control flows through said inlet and outlet conduitmeans so as to pressure said accumulator at said constant frequency andto open said accumulator to said outlet conduit means at said constantfrequency, and means to establish an output signal whenever the pressurein said outlet conduit means exceeds a predetermined value.
 9. Theapparatus of claim 8 wherein said means to establish an output signalcomprises a source of electrical energy, circuit means connected to saidsource, a switch in said circuit means, and pressure responsive meansconnected to said outlet conduit means to close said switch whenever thepressure in said outlet conduit means exceeds a predetermined value.